Devices, such as, ground penetrating radar, metal detectors, to name just a few, have been provided to sense objects buried beneath the surface of the earth. Such devices are normally mounted on a towed or pushed vehicle and moved over the underlying terrain to sense buried objects. Such devices have been used separately or together to improve the accuracy of object sensing. These devices deliver electromagnetic radiation signals and receive a reflection of the signals. Information related to the sensed object, based on signals received, is recorded and analyzed either immediately or at a later date, manually or electronically. The information identifying the object is normally associated with a pulse in a wave form. This information enables the location of the buried object to be marked on the ground surface when excavation or other geographic surface altering operation is to be subsequently performed or to be charted on a subsurface map of buried objects, such as pipes, electrical conduits, steel rod and other subsurface objects for future reference.
Recent developments in hardware and software associated with ground probing radar has improved the speed of ground data signal processing to the point where an object sensed can be displayed or recorded substantially immediately. Also, the accuracy of determining the envelope of the object displayed, based on the processed signals, has improved to the point where even the identity of the object can be manually ascertained.
Geographic surface altering machines, such as, dozers, scrapers, motorgraders, pavement profilers, road reclaimers, just to name a few, operate work in environments in which buried or partially buried objects are present. It is important that such objects are avoided in order that damage to the object or the machine can be prevented.
Attempts to apply ground penetrating object detection technology to geographic surface altering machinery for the purpose of automatically controlling a work implement on the machine has been unsuccessful. One reason for this is that earlier computer technology has not been capable of processing data fast enough to enable a realtime application to implement position control. Further, the physical size of the ground penetrating device has limited the usage to trailer or other mobile carrying vehicles. Recent advancements in the speed of signal processing and the ability to accurately identify subsurface objects has made realtime identification feasible.
The problems of providing a control system that is responsive, accurate, and cost effective is a major concern and has not been demonstrated in the past. Automatic control of the elevational position of a work implement based on an undesirable object being identified in the path of movement of the work implement requires the knowledge of many parameters of operation. Parameters such as, the elevational position of the implement, the rate of travel of the machine, speed of elevational movement of the implement, and the elevational position of the undesirable object relative to the work implement, just to name a few. These parameters along with others must be taken into consideration if automatic control is to be achieved.
The present invention is directed to overcoming one or more of the problems set forth above.